Telephone-transmitter.



N. TANNAKAi TELEPHONE TRANSMITTER. APPLICATION FILED MAR. 21 m5.

Patented July 11,1916.

11W VEJV W NAHO TANNAKA, OF N W YORK,-1\T. Y.

TELEPHONE-TRANSMITTER.

Application filed March 27, 1915.

To all whom it may concern:

Be it known that I, NAHO TANNAKA, a subject of the Emperor of Japan, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Telephone-Transmitters, of which the following is a full, clear, and exact description.

This invention relates to improvements in a telephone transmitting apparatus, in which certain cushioning and other means are provided for the purposes of causing the original voice or sound to be transmitted substantially without distortion and of incivasing the current carrying capacity or the resistance variability of the transmitter.

With transmitters now in general use, sound is more or less modified, having extraneous sound vibrations introduced therewith upon the diaphragm or otherwise distorted, especially so when spoken with the mouth close to the transmitter mouth piece. To overcome this defect without drawback in transmission efficiency is the aim of the present invention;

Vith the above and other objects in view, the invention resides in the peculiar combination and arrangement of .parts to be hereinafter more fully described, illustrated and claimed.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar numerals indicate similar parts in all the views, and in which Figure 1 'is a sectional view of a transmitter, embodying the invention, and Fig. 2 is a sectional view of the same on the line 22 of Fig. 1, partly broken away.

In" the drhwings, the numeral 10 designates a diaphragm of somewhat thick carbon (or of any other suitable material, having a carbon electrode or electrodes on its back surface). In parallel with the diaphragm, is placed an electrode supporting plate 11 of suitable insulating material, bearing on .the side of the diaphragm semicircular carbon plates 1:2, 12, portions of which form electrodes confronting the diaphragm (see Fig. 2). The narrow space between the diaphragm and the carbon plates is occupied and divided into several circular compartments by a soft washer or cushion 13 of felt or like material, as shown in Fig. 2, and the compartments are partly or fully filled with carbon grains or fine carbon balls 14.

Specification of Letters Patent.

Patented July 11.1, 1916.

Serial No. 17,564. i

The diaphragm 10 is provided with a ring cushion 15 of felt or like, and the electrode supporting plate, with a similar cushion 16 for separating them from the casing 17 within which they are contained. 1 found that the rigidity of the back electrodes or the electrode plate is not required, but in contrary, the elastic holding serves to eliminate certain ill effect on the diaphragm, that probably is due to the vibrations of the casing, caused by the vibrations of the bodies and air in contact or connection therewith The bottom of the casing is made in a form of a movable screw stopper 18' for the purpose of adjusting the pressure on the cushions. The edges of the diaphragm and the electrode supporting plate may be kept separated from the casing merely by pressing the cushions, care being taken to have them stationed at the center, so that the marginal portions of the cushions will keep them from contact with the casing. These cushions should be observed with distinction from damping springswhich are employed in some forms of transmitters merely to damp the vibrations of the diaphragms, and from insulating rubber pads or washers which are used to insulate their respective diaphragms from the casings. A diaphragm. if cushioned as herein set forth, acquires the vibratory property, no matter whether it is elastic or not, because of the tendency to return tothe initial position, when an external force is applied, moving it away therefrom. ith a diaphragm which is fixed or substantially fixed at its peripheral edge, the case is different, as the vibratory quality is due to the elasticity of the diaphragm itself, and the vibration is drum-wise.

In the construction shown in the drawings, the carbon contact means or microphones are connected in a parallel-series, however, these may be joined in parallel or in series, when desired.

The casing 17 is attached to a transmitter housing 19 and is provided with a mouth piece 20, the bottom of which is made as large as the space left at the front of the diaphragm, it being desirable to send sound over the whole surface alike as much as possible, instead of concentrating sound at the center thereof. The electrodes 12, 12 are led out by two fine wires to insulated binding posts 21 and As it is readily seen in the drawings, the

' and the method of operation will be readilydia hragm l0 and the electrode supporting plate 11 are free from hard contact with the casing 17. The term herein a hard contact I mean a contact between the surfaces of two hard bodies, enough to interfere with required movement of one of the bodies.

As the diaphragm 10' is adapted to vibrate substantially bodily or it is stiff.

enough to do .so' by virtueofthe cushions, it is apparent that theeifective cross section may be increased, when desired, merely by extending the carboncontact means any where desirable along the back of the diaphragm. Vith the transmitters having diaphragms which vibrate drunrwise, this increase can not be made advantageously beyond certain limit, because of the consequently increasing inertia of heavier electrodes, -01 of the inactiveness of such diaphragms at their outer portions.

The cushion at the back of the electrode supporting plate may" be dispensed with, but the clearness would consequentlybe sacrificed to a certain extent.

By the above described means, I attain my objects to transmit the clear natural voice, and to increase the current carrying capacity of the transmitter.

From, the foregoing description, taken in connection with the accompanying draw-.

ing's, in which I have illustrated the apparatus and arrangement of parts as the best embodiment of my invention, the advantage of construction'and arrangement,

apparent to those skilled in the art to which this invention appertains, but I Wish it to be understood that the apparatus and arrangement shown herein a1*e merely illustrative, and that such changes maybe made, when desired, as to fall Witliinthe scope of the invention as claime 1 Having thus described :jthe invention, what I claim as new is 1. A telephone transmitteg comprising the combination with a casing; of a diaphragm cushioned bya yielding member against the casing, so as to enable the diaphragm to vibrate bodily in the intended operations, a plurality of carbon contact means disposed along thejbackof, the diaphragm, having their efiective cross section extended to the outer or edge portion thereof, an electrode holder or supporter bearing electrodes for said carbon contact means, a washer forming compartments for the contact means, and a cushion yieldingly separating the electrode holder or supporter from the casing.

2. A telephone transmitter, comprising a casing, a diaphragm cushioned around the peripheral edge portion thereof by a yielding member against the casing, an electrode supporter, a mouth piece in front of the diaphragm, its bottom being nearly equal in area to the exposed surface of the diaphragm,

variable resistance means partitioned by a yielding washer and disposed between the diaphragm and the electrode supporter, in engagement therewith, and a soft cushion supporting the electrode supporter against the casing.

8. A telephone transmitter, comprising the combination with a casing; of a diaphragm, carbon contacts in cooperative relation therewith for transmitting sounds, an electrode holder or supporter bearing electrodes for said carboncontacts, a washer separating the diaphragm and the electrodes, and sealing the carbon contacts, and blankets yieldingly holding under a pressure the diaphragm and the electrode holder or supporter, without making hard contact with the casing, the arrangement thereby allowing bodily vibrations of the diaphragm in the intended operations.

4. A telephone transmitter, comprising a casing, a diaphragm suliiciently still to vibrate substantially bodily under the stresses of the intended operations, a plurality of variable resistance means in cooperative relation with the diaphragm, portions of which serve as intern'iediate elecphragm at the central andthe outer portionsof said surface, an electrode holder bearing electrodes'for the carbon contact -means, and cushions which hold under a pressure the above described members in an operative position, without hard contact between the casing and the other members, said diaphragm thereby being able to vibrate bodily in the intended operations.

6. A telephone transmitter, comprising the combination with a casing; of adiahragm, carbon contact means subdivided by a yielding Washer and arrangedin engagement with the back surface of the diaphragm at suitable portions of said surface,

a without concentrating at the center thereof,

an electrode holder or supporter secured with the casing and bearing electrodes for said carbon contact means, and cushions yieldingly separating thediaphragm from the casing, the arrangement thereby allowing the diaphragm to vibrate simultaneously at the central and the outer portions thereof in the intended operations.

7. A telephone transmitter, comprising a diaphragm having carbon electrodes there- With'or thereon, a plurality of variable resistance means all connected in the same electrical circuit in engagement with said electrodes Which are distributed all over the back of the diaphragm, Without concentrating at the central portion thereof of the diaphragm, an electrode supporter bearing the other electrodes for said variable resistance means, and cushions or Washers under a pressure sealing said means, and yieldingly holding the above mentioned members within a frame. I

8. In a' telephone transmitter, a casing or frame, a carbon bearing diaphragm, carbon granules closed by a yielding Washer and disposed along the central and outer portions of the back of the diaphragm, a holder holding an electrode for said carbon granules, and cushions holding the above described members under pressure Without direct engagement between said members and the casing or frame.

9. A telephone transmitter, comprising the combination with a casing; of a diaphragm sufiiciently rigid to vibrate substantially bodily under the stresses of the intended operation, carbon contact means disposed in engagement with the back of the diaphragm, having the effective cross section extended to the outer portion of said back of the diaphragm, an electrode holder or supporter resiliently secured with the casing and bearing electrodes for said con-' tact means, and cushions yieldingly separating the diaphragm from the casing at the front.

10. In a telephone transmitter, a casing or frame, a carbon bearing diaphragm cushioned around the peripheral edge portion thereof by a washer against the casing or frame, carbon granules subdivided. by a yielding member and arranged along the back of the diaphragm without concentrating at the central portion of the latter, an electrode hearing plate in engagement With said carbon granules, and an elastic member yieldingly supporting said plate under pressure.

In testimony whereof I affix my signature in presence of two witnesses.

NAHO TANNAKA.

Witnesses:

CHARLES A. DUNN, KAIsER SAKAINo.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

- Washington, D. G. 

